Characterization of biologically active, platelet-derived growth factor-like molecules produced by murine erythroid cells in vitro and in vivo.
Platelet-derived growth factor (PDGF) is an important serum regulator of erythropoiesis in vitro. We have now obtained evidence suggesting that PDGF-like molecules may also modulate erythropoiesis in vivo. Western blot analysis of cytoplasmic extracts from Rauscher murine erythroleukemia cells and phenylhydrazine-treated mouse splenic erythroid cells revealed the presence of several PDGF-like proteins. The presence of PDGF-like proteins in the cytoplasm of these two erythroid cell types was confirmed by immunohistochemical staining. Using a serum-free biologic assay, PDGF-like biological activity was found in cell lysates and conditioned medium of both Rauscher cells and phenylhydrazine-treated mouse erythroid cells. Subcellular localization experiments revealed the biological activity to be concentrated in the cytosolic fraction. Using a series of antibodies to hematopoietic growth factors we demonstrated that PDGF-like biological activity was specifically immunoprecipitated by both monoclonal and polyclonal anti-human PDGF antibodies but not by antibodies to burst-promoting activity, granulocyte-macrophage colony-stimulating factor, IL-3, or erythropoietin. Taken together, the data are consistent with the hypothesis that PDGF-like molecules play a role in the regulation of mammalian erythropoiesis in vivo.
Sytkowski
A J
AJ
Department of Medicine, New England Deaconess Hospital, Harvard Medical School, Boston, Massachusetts 02215.
O'Hara
C
C
Vanasse
G
G
Armstrong
M J
MJ
Kreczko
S
S
Dainiak
N
N
D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D002478:Cells, Cultured; D002999:Clone Cells; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D007150:Immunohistochemistry; D004915:Leukemia, Erythroblastic, Acute; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive; D008214:Lymphocytes / Q000378:metabolism*; D051379:Mice; D010982:Platelet-Derived Growth Factor / Q000096:biosynthesis* / Q000302:isolation & purification / Q000494:pharmacology; D013347:Subcellular Fractions / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000378:metabolism*
D010982:Platelet-Derived Growth Factor